Dome switches, which typically hold a small volume of air, are generally vented to atmosphere or to a buffer air volume in order to avoid significant increase in air pressure inside a given dome switch when it is depressed. Without providing such venting, or buffer air volume, repeated depression of the dome switches, and therefore the repeated air pressure increase/decrease cycle, can cause early failure. Further, such venting of dome switches, or buffer air volume, is desirable in order for the switches to have a tactile feel that is clear and sharp to the user.
Mobile electronic devices may include one or more dome switches. In many cases, such a mobile electronic device will have an array of domes switches with each dome switch of the array being in fluid communication with the other dome switches and, with the interior of their related mobile device. In such cases, the depression of one dome switch causes the air therein to flow towards the other dome switches and towards the interior of the mobile electronic device. Release of the depressed dome switch causes a reverse flow of air into the dome switch in question. Such arrays of dome switches may be susceptible to moisture and dust particulates present in the inside of the mobile electronic device. Further, having such humidity and dust particulates repeatedly flow inside the mobile electronic device can give rise to electrical charge accumulation and discharge, which can be deleterious to the operation of the mobile electronic device. This is a particular concern when the mobile electronic device in question is not sealed from the atmosphere, making it prone to variations in humidity and dust in the atmosphere.
In other mobile electronic devices, an array of dome switches has each of its dome switches in fluid communication with each other and with a dedicated sealed air chamber mounted inside its related mobile device. The presence of such dedicated air chambers has a significant effect on the size of the mobile devices.
In yet other personal communication mobile devices, the dome switches are in fluid communication only with each other, not with the interior of the mobile electronic device, or with a dedicated air chamber. Having the dome switches in communication only with each other makes for an increase in complexity of the manufacturing and testing of the mobile device.
Improvements in dome switches are therefore desirable.